You make a mistake to focus on the technology behind his access. The rules governing simple technological processes and the legal definition of "intent" are very important here.
Going to the driver's license bureau and applying for a new license is not a crime--even is you use a different name. My wife has done this a few times, once when we got married to change here last name, and again when she decided that that she no longer wanted to be know by her middle name (as she had done for years) and wanted to start using her legal first name. Her intent was to manage her identity. If, on the other hand, she was accessing new credentials with the "intent" of defrauding, avoiding taxes or other debts, or evading a criminal prosecution, it is an entirely different matter.
It was not the act of changing a MAC address, it was the intent of concealment that was the crime in the context of doing something that he knew or reasonably supposed to be "legally wrong" and thus a valid charge. An alternate legal description / argument is "awareness of guilt."
I am not saying that I would have filed the charges myself or that they would have ultimately prevailed. i am only saying that it is not the act that is the issue and that the attorney general is not as far out of line as represented in the article.
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